The Menin story in acute myeloid leukaemia-The road to success.

The treatment of acute myeloid leukaemia (AML) has changed fundamentally in the last decade with many new targeted therapies entering clinics. Some of the most interesting agents under development are Menin inhibitors which interfere with the interaction of Menin with wild-type (wt) KMT2A or a KMT2A-fusion protein and thereby downregulate the leukaemic gene expression (MEIS1, PBX3, HOX) in NPM1 mutant or KMT2A-rearranged leukaemia. Other HOX and MEIS1 expressing leukaemias may also be sensitive to Menin inhibition. Following the encouraging results as monotherapy in refractory and relapsed AML, the combination of Menin inhibitors with chemotherapeutic agents and other targeted drugs is being investigated clinically.

PAX5 alterations in an infant case of KMT2A-rearranged leukemia with lineage switch.

Lineage switch is a rare event at leukemic relapse. While mostly known to occur in KMT2A-rearranged infant leukemia, the underlying mechanism is yet to be depicted. This case report describes a female infant who achieved remission of KMT2A-MLLT3-rearranged acute monocytic leukemia, but 6 months thereafter, relapsed as KMT2A-MLLT3-rearranged acute lymphocytic leukemia. Whole exome sequencing of the bone marrow obtained pre-post lineage switch revealed two somatic mutations of PAX5 in the relapse sample. These two PAX5 alterations were suggested to be loss of function, thus to have played the driver role in the lineage switch from acute monocytic leukemia to acute lymphocytic leukemia.

Poor treatment responses were related to poor outcomes in pediatric B cell acute lymphoblastic leukemia with KMT2A rearrangements.

BACKGROUND: The KMT2A gene, formerly named the MLL gene, is rearranged (KMT2Ar) in 70-75% of infants, 5-6% of children and 10-15% of adult patients with B cell acute lymphoblastic leukemia (B-ALL). The outcome after chemotherapy of pediatric cases remains poor, and only a few studies have investigated the clinical and laboratory features, treatment response and prognosis in Chinese populations. METHODS: A total of 48 B-ALL children with KMT2Ar were enrolled in the study, and clinical and laboratory data were collected and analyzed by age group. The relationship between prognosis and traditional risk factors and treatment response was investigated for these patients who received chemotherapy. RESULTS: The 48 enrolled patients included 28 males and 20 females; 18 (37.50%) or 30 (62.50%) patients were an age of < 12 m (infant B-ALL) or of > 12 m at onset. An initial WBC count of 300 × 109/L was detected in 7 (14.58%) patients; testicular leukemia (TL) or central nervous system involvement was found in 5 (10.41%) or 3 (6.25%) patients, respectively. Statistical differences were not found in the age groups of sex or initial WBC count, whereas TL was more common in the infant group (P < 0.05). 11q23 was detected in 18 patients; KMT2Ar was detected in 46 (95.83%) or 45 (93.75%) patients by FISH or multiplex RT-PCR technology, respectively; RNA-seq data were obtained for 18 patients, and 3 patients with uncommon KMT2Ar were identified. KMT2A-AFF1, KMT2A-MLLT3 and KMT2A-MLLT1 were the most common transcripts. Statistical differences were not found in treatment response by age groups, including dexamethasone induction, bone marrow (BM) smear status and minimal residual disease (MRD) level at different time points (TP), treatment-related mortality (TRM), or complete remission (CR) rate (P > 0.05); MRD levels monitored by FCM or PCR were unequal at the same TP. Four patients died of treatment, and TRM was 8.33%; 40 patients achieved CR, and the CR rate for the cohort was 83.33%. Seven patients quit, 15 patients relapsed, and the 5 yr cumulative relapse rate was 59.16 ± 9.16%; the 5 yr prospective EFS (pEFS) for patients who were included or excluded from the TRM group was 36.86 ± 8.48% or 40.84 ± 9.16%, respectively. Multivariate analysis for prognosis and hazard ratio was performed for 37 patients without TRM and revealed that an initial WBC count of > 300 × 109/L and a positive level of FCM-MRD were strongly related to a poor outcome for B-ALL patients with KMT2Ar (P < 0.05).

Molecular Classification and Overcoming Therapy Resistance for Acute Myeloid Leukemia with Adverse Genetic Factors.

The European LeukemiaNet (ELN) criteria define the adverse genetic factors of acute myeloid leukemia (AML). AML with adverse genetic factors uniformly shows resistance to standard chemotherapy and is associated with poor prognosis. Here, we focus on the biological background and real-world etiology of these adverse genetic factors and then describe a strategy to overcome the clinical disadvantages in terms of targeting pivotal molecular mechanisms. Different adverse genetic factors often rely on common pathways. KMT2A rearrangement, DEK-NUP214 fusion, and NPM1 mutation are associated with the upregulation of HOX genes. The dominant tyrosine kinase activity of the mutant FLT3 or BCR-ABL1 fusion proteins is transduced by the AKT-mTOR, MAPK-ERK, and STAT5 pathways. Concurrent mutations of ASXL1 and RUNX1 are associated with activated AKT. Both TP53 mutation and mis-expressed MECOM are related to impaired apoptosis. Clinical data suggest that adverse genetic factors can be found in at least one in eight AML patients and appear to accumulate in relapsed/refractory cases. TP53 mutation is associated with particularly poor prognosis. Molecular-targeted therapies focusing on specific genomic abnormalities, such as FLT3, KMT2A, and TP53, have been developed and have demonstrated promising results.

Acute Leukemia in Infants.

PURPOSE OF THE REVIEW: Infant leukemia is a rare, distinct subgroup of pediatric acute leukemias diagnosed in children under 1 year of age and characterized by unique, aggressive biology. Here, we review its clinical presentation, underlying molecular biology, current treatment strategies, and novel therapeutic approaches. RECENT FINDINGS: Infant leukemias are associated with high-risk molecular features and high rates of chemotherapy resistance. International collaborative clinical trials have led to better understanding of the underlying molecular biology, refined risk-based stratification, and investigated the use of hematopoietic stem cell transplantation. However, intensification of chemotherapy has failed to improve outcomes, and current regimens are associated with significant treatment-related and long-term toxicities. Infants with leukemia remain a challenging group to treat. We must continue collaborative efforts to move beyond traditional cytotoxic chemotherapy, incorporate molecularly targeted strategies and immunotherapy, and increase access to clinical trials to improve outcomes for this high-risk group of patients.

Cytogenetic and Fluorescence in situ Hybridization Profile of Pediatric Acute Lymphoblastic Leukemia in a University Hospital in South India.

OBJECTIVE: The purpose of this study was to evaluate the cytogenetic and fluorescent in situ hybridization (FISH) profile in children with acute lymphoblastic leukemia (ALL), referred to a university hospital in a 5-year 6-month period. SUBJECTS AND METHODS: Cytogenetic analysis of the bone marrow aspirate specimens of 91 patients was performed by standard Giemsa (G)-banding and interphase FISH (iFISH). RESULTS: The frequency of chromosomal abnormalities detected by G-banding was 29.5%, and the frequency of nonrandom abnormalities with independent prognostic significance identified by iFISH was 46.4%. The abnormality with the highest frequency was gain of RUNX1 (n = 18, 21.4%), followed by ETV6/RUNX1 fusion (n = 7, 8.3%), and gain of KMT2A (n = 6, 7.1%). Additionally, rarely reported gains of ETV6, PBX1, and ABL1 were observed at a frequency of 6% (n = 5), and the deletion of ETV6 and TCF3 was seen at a frequency of 3.6% (n = 3) and 2.3% (n = 2), respectively. A 10-year old with intrachromosomal amplification of chromosome 21 was also observed. CONCLUSIONS: This study strengthens and widens the current knowledge of the cytogenetic landscape of pediatric ALL.

First case of B ALL with KMT2A-MAML2 rearrangement: a case report.

BACKGROUND: A large number of chromosomal translocations of the human KMT2A gene, better known as the MLL gene, have so far been characterized. Genetic rearrangements involving KMT2A gene are frequently involved in lymphoid, myeloid and mixed lineage leukemia. One of its rare fusion partners, the mastermind like 2 (MAML2) gene has been reported in four cases of myeloid neoplasms after chemotherapy so far: two acute myeloid leukemias (AML) and two myelodysplasic syndrome (MDS), and two cases of secondary T-cell acute lymphoblastic leukemia (T-ALL). CASE PRESENTATION: Here we report the case of a KMT2A - MAML2 fusion discovered by Next-Generation Sequencing (NGS) analysis in front of an inv11 (q21q23) present in a 47-year-old female previously treated for a sarcoma in 2014, who had a B acute lymphoid leukemia (B ALL). CONCLUSION: It is, to our knowledge, the first case of B acute lymphoblastic leukemia with this fusion gene. At the molecular level, two rearrangements were detected using RNA sequencing juxtaposing exon 7 to exon 2 and exon 9 to intron 1-2 of the KMT2A and MAML2 genes respectively, and one rearrangement using Sanger sequencing juxtaposing exon 8 and exon 2.

A case of AML with complex karyotype and chromosomal rearrangement of KMT2A.

This is a case of an elderly patient diagnosed with acute myeloid leukemia (AML). While morphological findings, including numerous long, slender, cigar-shaped Auer rods, suggested AML with t(8;21), cytogenetic and FISH analysis revealed abnormalities in chromosome 11 and the KMT2A (MLL) gene. The patient also exhibited double minutes, typically seen in AML and linked to a complex karyotype and poor prognosis. Correlating morphological findings with molecular genetics and cytogenetics is crucial for accurate diagnosis and treatment.

Monocytic and blastic plasmacytoid dendritic cell differentiation in acute leukemia with KMT2A rearrangement.

Acute leukemia with KMT2A rearrangement shows a spectrum of immunophenotypic presentation, but blastic plasmacytoid dendritic cell differentiation is extremely rare. Here we present a case of KMT2A rearranged acute leukemia with a hybrid immunophenotype in which a single blast population showed both blastic plasmacytoid dendritic cell and monocytic differentiation. This unusual case contributes to the diversity of the immunophenotypic spectrum in KMT2A rearranged acute leukemia and also sheds light on the cell of origin of plasmacytoid dendritic cells.

Prevalence of Gene Rearrangement by Multiplex PCR in De Novo Acute Myeloid Leukemia in Adult Iraqi Patients.

Introduction: Gene rearrangements of acute myeloid leukemia (AML) play a significant role in categorizing patients and provide valuable information about prognosis and treatment choices. However, in Iraq, the prevalence and prognostic significance of gene rearrangements in AML have not been previously examined. Methods: This study utilized a multiplex reverse transcription real-time PCR (RT-qPCR) system to identify gene rearrangements in a group of 115 adult patients from Iraq who had been diagnosed with De Novo AML. The diagnosis of AML was confirmed through blood film and flow cytometry. The ethical committee of the College of Medicine at the University of Baghdad provided approval for this research study. Results: In this study, 66.1% of the patients diagnosed with acute myeloid leukemia (AML) exhibited distinct genetic abnormalities. Among these abnormalities, the most frequent was the rearrangement involving the KMT2A gene, observed in 19.9% of the patients. The risk stratification analysis revealed that 40% of the patients were classified as having a favorable risk, 4.3% as intermediate risk, and 25.2% as adverse risk. A subtype of AML known as core-binding factor (CBF) AML was identified in 21.7% of the cases, with 84% of these patients achieving complete remission. The NPM-RARA gene rearrangement, found in 43% of acute promyelocytic leukemia (APL) cases, was associated with a 71% complete remission rate. Among patients with KMT2A rearrangement, which accounted for 19.9% of all AML cases, the MLL-AF10 rearrangement was the most common, although only one patient with KMT2A rearrangement achieved complete remission. Furthermore, the analysis of demographic data revealed a significant association between increased risk and advanced age, presence of comorbidities, and FAB classification (M0 subtype). Conclusion: The prevalence of genetic rearrangements in Iraqi De Novo AML patients is higher than the global trend, highlighting the importance of genetic characterization in risk assessment and treatment decisions.

Younger age and induction failure predict outcomes in infant leukemia: 30 years of experience in a tertiary center.

Objectives: This study aimed to evaluate the characteristics and outcomes of infant patients with leukemia. Methods: A retrospective analysis was conducted in a cohort of 39 patients diagnosed with infant leukemia from 1990 to 2020 who underwent treatment at the pediatric hemato-oncology department of a tertiary hospital in Madrid, Spain. Results: Of the 588 diagnosed cases of childhood leukemia, 39 (6.6%) cases were infant leukemia. The 5-year event-free survival and the 5-year overall survival were 43.6% (SE 4.1) and 46.5% (SD 24.08), respectively. In a univariate analysis, a younger age at diagnosis was associated with poorer outcomes (p = 0.027), as was induction failure (p = 0.0024). Patients treated with hematopoietic stem cell transplantation had better outcomes than non-transplanted patients (p = 0.001); however, the group comparisons that exclude patients who were unable to undergo transplantation due to refractoriness/relapse or death during treatment showed no significant differences. Conclusions: The main risk factors that affected survival in our study were an age younger than 6 months and a poor response to induction therapy. It is important to identify poor prognostic factors in this population in order to seek different approaches that could improve outcomes.

Repressing HIF-1α-induced HDAC9 contributes to the synergistic effect of venetoclax and MENIN inhibitor in KMT2Ar AML.

KMT2A-rearranged acute myeloid leukemia (KMT2Ar-AML) is an aggressive subtype of AML with poor response and prognosis. KMT2Ar-AML has been demonstrated to be sensitive to BCL2 inhibitor venetoclax (VEN), but these patients are unable to benefit from current VEN-based regimen (VEN plus azacitidine or low dose-cytarabine), so a novel and KMT2A rearrangement-specific targeting partner is required, and MENIN inhibitor (MEN1i) is a promising one. Herein, we investigated the effect and mechanism of VEN plus MEN1i in KMT2Ar-AML. Our results showed that VEN and MEN1i exhibited a striking synergistic effect in KMT2Ar-AML cell lines (in vitro), primary KMT2Ar-AML cells (ex vivo), and MOLM13 xenotransplantation model (in vivo). Furthermore, we found that VEN plus MEN1i significantly enhanced apoptotic induction in KMT2Ar-AML cell lines. VEN or MEN1i monotherapy disrupted balance of BCL-2/BCL-XL or down-regulated HOXA9/MEIS1, respectively, but these mechanisms were not further strengthened by their combination. RNA-Sequencing identified that HDAC9 was specifically repressed by VEN plus MEN1i rather than monotherapy. We demonstrated that HDAC9 was indispensable for KMT2Ar-AML proliferation and its repression contributed to proliferation inhibition of VEN plus MEN1i. Moreover, we found that hypoxia induced HDAC9 expression in KMT2Ar-AML, and VEN plus MEN1i inhibited hypoxia pathway, especially HIF-1A, and its target HDAC9. As our results indicated, VEN plus MEN1i-mediated HDAC9 down-regulation was partially dependent on HIF-1A repression in KMT2Ar-AML. Hypoxia induction sensitized KMT2Ar-AML to VEN plus MI-503-mediated proliferation inhibition and apoptosis induction. Therefore, repressing HIF-1A-induced HDAC9 contributed to the synergistic effect of VEN and MEN1i in KMT2Ar-AML.

Lineage switch of KMT2A-rearranged adult B-lineage acute lymphoblastic leukemia following bispecific T-cell engager and monoclonal antibody therapy.

Adult B-lineage acute lymphoblastic leukemia (B-ALL) with t(4;11)(q21;q23) is very rare. It is characterized by mixed-lineage leukemia and has the potential for lineage switching during the treatment course. We report the disease course of a patient with B-ALL with t(4;11)(q21;q23) to demonstrate that close monitoring of cell morphology and immunophenotyping is necessary to capture the lineage switch at an early stage. Cell morphology, immunophenotyping, and cytogenetics were used to evaluate the patient's disease status. A 36-year-old woman was diagnosed with B-ALL with t(4;11)(q21;q23), which encodes the KMT2A::AFF1 fusion. After the initial induction chemotherapy, her disease remained refractory, and the patient received salvage immunotherapy with blinatumomab and inotuzumab ozogamicin. However, the ALL did not respond. Repeated bone marrow examinations unexpectedly revealed the emergence of a major population of monoblasts, in addition to a minor population of the original B lymphoblasts. The patient was diagnosed with disease evolution from B-ALL to mixed-phenotype acute leukemia (MPAL, B/myeloid). We present this case to highlight the potential of KMT2A-rearranged B-ALL to undergo lineage switch following B-cell targeted therapy. Patients with this kind of B-ALL should therefore be closely monitored to capture potential changes in the nature of the disease and prompt appropriate treatment.

Mature B cell acute lymphoblastic leukaemia with KMT2A-MLLT3 transcripts in children: three case reports and literature reviews.

BACKGROUND: Mature B cell acute lymphoblastic leukaemia (BAL) is characterised by French-American-British (FAB)-L3 morphology and the presence of surface immunoglobulin (sIgM) light chain restriction. BAL is also considered as the leukaemic phase of Burkitt lymphoma (BL), in which t (8; 14) (q24; q32) or its variants are related to the myelocytomatosis oncogene (MYC) rearrangement (MYCr) is usually present. However, BAL with lysine methyltransferase 2A (KMT2A, previously called Mixed lineage leukaemia, MLL) gene rearrangement (KMT2Ar, previously called MLLr) is rare. RESULTS: Three BAL patients with KMT2Ar were enrolled between January 2017 and November 2019, accounting for 1.37% of the B-ALL population in our hospital. We also reviewed 24 previously reported cases of BAL and KMT2Ar and analysed the features, treatment, and prognosis. Total 13 males and 14 females were enrolled in our research, and the average age at diagnosis was 19.5 ± 4.95 months old. In these 27 patients, renal, central nervous system (CNS) and skin involvement were existent in 6, 4 and 3 patients, respectively; 26 patients (26/27) showed non-ALL-L3 morphology, while one patient is ALL-L3; overexpression of CD19 was detected in most cases, negative or suspicious expression of CD20 was found in 64% of patients. KMT2Ar was reported, but MYCr was not observed. 25 patients (25/27) achieved complete remission after chemotherapy or Stem cell transplantation. The patients were sensitive to chemotherapy, prospective event-free survival (pEFS) of BAL patients with KMT2Ar who received allogeneic haematopoietic stem cell transplantation (allo-HSCT) was higher than that in patients who received chemotherapy alone (83.33% vs 41.91%). CONCLUSION: BAL patients with KMT2Ar had unique manifestations, including younger age at diagnosis and overexpression of CD19; expression of CD20 was rare, and MYCr was undetectable. The pEFS was higher in patients undergoing allo-HSCT than in patients undergoing chemotherapy alone.

Advances of KMT2A rearrangment acute lymphoblastic leukemia in children / 中华实用儿科临床杂志

Lysine methyltransferase 2A( KMT2A) rearrangement (KMT2A-r) is a high-risk gene subtype of acute lymphoblastic leukemia (ALL) in children with a high relapse rate, poor prognosis and suboptimal response to conventional chemotherapy.Improving the treatment and prognosis of childhood KMT2A-r ALL is an urgent problem.In recent years, with an in-depth understanding of the mechanism of KMT2A-r, more accurate risk stratification of KMT2A-r ALL has been carried out, and great progress has also been made in its immune and targeted therapy.In this article, the genetic and biological characteristics, risk stratification, treatment strategies and prognosis of children KMT2A-r ALL were reviewed in order to provide theoretical support for clinical work and future research.

Cytogenetics and associated mutation profile in patients with acute monocytic leukemia.

INTRODUCTION: Cytogenetics and molecular testings for disease classifying and prognosis estimation are becoming routine in clinical practice. However, the molecular characteristics of acute monocytic leukemia (AML-M5) remain unclear. The aim of this study was to investigate the association between karyotypes and gene mutations, especially in AML-M5 patients with 11q23/KMT2A (MLL) rearrangement and normal karyotype. METHODS: A total of 126 de novo AML-M5 patients were screened for mutations in the 51 genes known or suspected to have a role in myeloid malignancies or in monocytic differentiation using next-generation sequencing (NGS). Chromosome karyotype analysis was performed by R-banding method and further confirmed either by fluorescence in situ hybridization (FISH) and/or by multiple reverse transcription polymerase chain reaction (multiple RT-PCR). RESULTS: Of the 126 patients, one or more mutations were detected in 83.3% patients. FLT3-ITD and NRAS had the highest mutation frequency, followed by NPM1, DNMT3A, TET2, KRAS, and RUNX1. We also identified a significant difference in mutational spectrums between KMT2A-rearranged (KMT2Ar) patients and normal karyotype (NK) patients, as reflected in the average number of gene mutations per patient (1.66 vs 2.46), and in the frequencies of commonly mutated genes (FLT3-ITD: 6% vs 43.5%; NPM1: 0% vs 43.5%; RUNX1: 2.0% vs 15.2%; DNMT3A: 4% vs 26.1%; KRAS: 24.0% vs 4.35%). Patients harboring ≥3 mutations showed much lower complete remission rate than that with double mutations (P = 0.043) in high-risk group. CONCLUSION: There was a significantly different mutation profile between KMT2Ar-patients and NK patients. Our research provided new insight into the molecular characteristics of AML-M5.

Hematopoietic stem cell transplantation for pediatric acute myeloid leukemia patients with KMT2A rearrangement; A nationwide retrospective analysis in Japan.

OBJECTIVE: Pediatric acute myeloid leukemia (AML) with KMT2A rearrangement is detected in 15-20% of all pediatric AML patients and is associated with adverse outcomes even after allogeneic hematopoietic stem cell transplantation (HSCT). To investigate outcomes and prognostic factors, we investigated 90 pediatric AML patients with KMT2A rearrangement after allogeneic HSCT. METHODS: We retrospectively analyzed Japanese registration data for patients who had received allogeneic HSCT between 1988 and 2011. Median age was 3 years (range, 0-15 years), and no gender difference was evident. Median observation period was 119 months. RESULTS: The 3-year overall survival (OS) rate of KMT2A-rearranged AML was 52.1% (95% confidence interval (CI), 42.4-64%, n = 90), and the 3-year disease-free survival (DFS) rate was 46.7% (95%CI, 36.8-58.2%). The 3-year DFS of KMT2A-rearranged AML was not significantly poorer than that of other AML (P = 0.09), and no significant difference was also seen in 3-year OS rate (P = 0.21). Multivariate analysis showed disease status (complete remission) at HSCT was associated with better outcomes. A significant difference in treatment-related mortality (TRM) was apparent between HSCT from a HLA full-matched related donor and that from a haploidentical donor (P = 0.001). DISCUSSION: HSCT is a curative option for pediatric AML with KMT2A rearrangement. Pretransplant status was the most significant prognostic indicator for relapse and survival. Enhancing supportive therapy to reduce TRM will further improve treatment outcomes of KMT2A-rearranged pediatric AML.